kernel vec4 minPlus(sampler image, float y)
{
	vec4 samplerExtent = samplerExtent(image);
	
	vec2 c = samplerCoord(image);
	vec2 cup = c + vec2(0.0, 1.0);
	vec2 cupl = c + vec2(-1.0, 1.0);
	vec2 cupr = c + vec2(1.0, 1.0);
	
	float best = sample(image, cup);
	float upl = sample(image, cupl);
	float upr = sample(image, cupr);
	best = c.x <= samplerExtent.x + 1.0 ? best : min(best, upl);
	best = c.x >= samplerExtent.x + samplerExtent.w ? best : min(best, upr);
	
	float me = sample(image, c);
	float ret = best + me;
	return vec4(ret, ret, ret, 1.0);
}